An image projector and a light tunnel are provided. The light tunnel includes: a light guide path in a form of a hollow tube having inner surfaces to reflect and guide light; a light entrance to allow light to enter the light guide path and a light exit to emit the light guided by the light guide path. The inner surfaces of the light guide path include inclined surfaces which are inclined in a manner that the aperture of the light guide path increases towards the light entrance. These inclined surfaces are connected to the light entrance. The aperture of the light entrance is larger than the aperture of the light exit. An image projector with this light tunnel allows more light to enter the light guide path than in the case of prior art, thereby decreasing light loss and increasing light quantity usable for image display.
A light tunnel includes a first optical element, a second optical element, a third optical element and a fourth optical element. The first optical element has a first recess. The second optical element is disposed opposite to the first optical element and has a second recess. The third optical element connects the first optical element with the second optical element and has one end disposed in the first recess or the second recess. The fourth optical element is disposed opposite to the third optical element, connects the first optical element with the second optical element, and has one end disposed in the first recess or the second recess. Inner surfaces of the first to fourth optical elements form a light passage. A projection system is also disclosed.
